Mersenne: Re: DWT help

[EWMAYER]

Jason Papadopoulos <[EMAIL PROTECTED]> wrote

>To perform a DWT, you need to find a prime that
>
>    1) allows a number theoretic FFT of large size, say 2^n, and
>    2) allows a number r such that r^(2^n) = 2, i.e. a large root of 2
>
>{snip}
>In practice, primes that satisfy property 1 seem very common but those
>which satisfy both properties simultaneously are much more rare (there
>are no 32-bit primes I know of which can work).

Jason, I believe on this latter point you mean strictly *real* primes - as
we both know, the Gaussian integers over GF(q^2) (with q a Mersenne prime)
have both large power-of-2 roots of unity and of 2, and moreover, the latter
have a very nice form (real powers of 2, i.e. the DWT weights multiplies
can be effected via simple shifts.)

-Ernst